US9920778B2 - Valve for the temperature-dependent control of at least one hydraulic load - Google Patents

Valve for the temperature-dependent control of at least one hydraulic load Download PDF

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Publication number
US9920778B2
US9920778B2 US14/648,929 US201314648929A US9920778B2 US 9920778 B2 US9920778 B2 US 9920778B2 US 201314648929 A US201314648929 A US 201314648929A US 9920778 B2 US9920778 B2 US 9920778B2
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Prior art keywords
piston
fluid
connection
control
choke
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US20150308468A1 (en
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Ralf Bosch
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Hydac Drive Center GmbH
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Hydac Drive Center GmbH
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/04—Special measures taken in connection with the properties of the fluid
    • F15B21/042—Controlling the temperature of the fluid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D25/00—Pumping installations or systems
    • F04D25/02—Units comprising pumps and their driving means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/004—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by varying driving speed
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/01—Control of temperature without auxiliary power
    • G05D23/02—Control of temperature without auxiliary power with sensing element expanding and contracting in response to changes of temperature
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

  • the invention relates to a valve for the temperature-dependent control of at least one hydraulic load.
  • the valve comprises a valve housing having at least one tank connection, at least one working connection and at least one supply connection and comprises a control piston for controlling those connections.
  • the control piston is movably disposed in the valve housing and preloaded by an energy store, such as a working spring.
  • a thermal element can be supplied with a fluid at a specifiable temperature, and is actively coupled with the control piston.
  • the invention relates to a hydraulic system, which contains at least one such valve.
  • the object of a cooling device is to dissipate this heat from the hydraulic system.
  • the fan of a cooling device can typically be driven hydraulically.
  • the hydraulic drive unit for an allocated hydraulic motor may be designed as a separate circuit, which is independent of the circuit of the fluid that is to be cooled.
  • a valve of the above mentioned type is known from the subsequently published DE 10 2012 008 480.3.
  • the known valve is used to actuate a hydraulic drive of a fan as a function of the temperature of the fluid that is to be cooled, or more precisely, to predetermine the speed of the fan.
  • the valve and the fan drive, which is actuated by the valve are disposed in a joint hydraulic circuit. Room for improvement still exists in the use of the known valve in sluggish hydraulic systems having more limited adjustment dynamics.
  • limiting the control pressure predetermined by the valve is desirable to be able to protect the thermal element against overloads.
  • An object of the invention is to expand the area of application for the valve, in particular to include sluggish hydraulic systems having more limited adjustment dynamics, and to make additional functions available to the valve to improve the manner in which the valve operates.
  • thermo element and the control piston are two separate components and may be disposed in the valve housing in a joint fluid chamber.
  • the fluid for example a medium that is to be cooled, flows onto, about or through the thermal element, also referred to as the thermal working element, and takes on the temperature of the thermal working element.
  • the thermal element causes a movement, compression or expansion, of the energy store. Accordingly, a change in the initial load on the energy store predetermines the pressure that is to be regulated by the control piston, also referred to as the main control piston.
  • a valve according to the invention By using the energy store, which is typically designed as a compression spring, thus as a working spring, a valve according to the invention, in particular, can be used for the regulation of sluggish hydraulic systems having more limited adjustment dynamics.
  • the solution according to the invention is absolutely usable for highly dynamic applications as well.
  • a choke piston which can be moved in the valve housing, is disposed between the thermal element and the control piston.
  • the choke piston is, in particular, connected to the thermal element in an operative connection on the one side, preferably via an actuating element, and is connected to the energy store in an operative connection on the other side.
  • the energy store is in an operative connection with the control piston at the end of the energy store that faces away from the choke piston.
  • the energy store is connected to the choke piston.
  • An actuating element for example a push rod, is advantageously formed on the thermal element, which actuating element generates a movement in a working direction, also referred to as an travel distance, with a simultaneous increase of force at the choke piston as the temperature of the fluid increases.
  • the actuating element advantageously rests against the choke piston and moves the choke piston in accordance with its temperature-dependent travel distance. The travel distance and the associated force are transferred to the energy store via the choke piston.
  • a P-T fluid connection is formed in the valve housing from the supply connection to the tank connection.
  • the P-T fluid connection can be controlled by the choke piston.
  • the choke piston closes or at least partially opens the P-T fluid connection in accordance with a travel distance of the thermal element.
  • the choke piston opens an increasing choke cross section from the supply connection to the tank connection over the travel distance, or in other words, over the movement of the thermal element.
  • a P-A fluid connection from the supply connection to the working connection, at which the operating pressure that is to be regulated prevails, is typically formed on the control piston, which serves as the main control piston.
  • At least one input choke is provided, which is allocated to the supply connection, and which is preferably disposed in at least one fluid arm in the valve housing allocated to the supply connection.
  • the pressure differential across the input choke is increased in accordance with an increasing choke cross section of the choke piston.
  • the system pressure in the hydraulic system allocated to the hydraulic load must increase disproportionately to maintain a balance of forces at the control piston. For this reason, a linear pressure-temperature characteristic curve can be adapted to the required characteristic curve of a load, for example, a disproportionately increasing characteristic curve of a fan, such as the cube thereof.
  • the thermal element can be in an operative connection with an overload element, such as an overload spring, preferably with a compression spring, at the end of the thermal element that is facing away from the control piston.
  • the thermal element can be connected to the overload element.
  • the overload element limits the initial load or, respectively, the force applied to the control piston via the energy store.
  • a kind of pressure limitation is implemented in such a way that, in the case of a system pressure that exceeds the maximum allowable value, the control piston is brought into full contact with the thermal element via the choke piston, and the pressure that is to be regulated exerts a force on the overload element at the thermal element.
  • the pressure that is to be regulated is limited to the value that is predetermined by the overload element, and as a result, the thermal element is protected against an overload.
  • control piston has a main piston component and a second piston component as differential pistons on a joint piston rod.
  • the second piston component has a different effective piston surface as compared to the main piston component.
  • a first fluid chamber is delimited, into which the supply connection discharges.
  • the main piston component controls the outlet cross-section between the first fluid chamber and the working connection with control edges or control notches.
  • connection line from the first fluid chamber to the choke piston may also be present in the valve housing.
  • the fluid passage between the connection line and the branch line can be controlled by the choke piston.
  • a fluid return that extends from the thermal element to the tank connection can be provided and preferably also extends in the valve housing.
  • the fluid feed and the fluid return form an internal flushing fluid channel for subjecting the thermal element to a thermal load.
  • a fluid path may be formed between external fluid connections in the valve housing for the fluid, which fluid defines the temperature of the thermal element.
  • the thermal element is disposed in the fluid path.
  • an external fluid port is use, wherein the fluid or, respectively, the flushing fluid is not returned internally via the valve or, respectively, pump housing, but instead, is returned externally.
  • At least one external fluid port which is allocated to the thermal element, may be formed in the valve housing.
  • the invention also relates to a hydraulic system having at least one hydraulic load and at least one valve according to the invention for the temperature-dependent control of the at least one hydraulic load.
  • the hydraulic load is connected to the working connection of the valve.
  • the control piston at least partially opens or closes a P-A fluid connection from the supply connection to the working connection according to the temperature of the thermal element.
  • At least one hydraulic load may be allocated to a hydraulic motor, which, together with a variable displacement pump, forms a hydraulic system, in particular a motor pump unit.
  • the respective hydraulic load influences the displacement volume of the variable displacement pump, and in particular, predetermines the swivel angle thereof, preferably via a back coupling of the operating pressure.
  • a temperature-dependent control of the hydraulic motor and, as a result, the motor power thereof is implemented. Due to the function-related use of at least one or, advantageously, a plurality of springs, especially preferably, compression springs connected in series, a temperature-dependent regulation of a sluggish hydraulic system having more limited adjustment dynamics is achieved.
  • the corresponding hydraulic load is advantageously designed as a actuating cylinder, which is connected to the working connection of the valve on the working side.
  • the piston of said actuating cylinder predetermines the pivot angle of the variable displacement pump.
  • the hydraulic motor drives a fan of a cooling device having a fan speed, which is predetermined by the hydraulic system.
  • an axial piston pump having an integrated temperature control valve is provided as a fan drive without the use of electrical or electronic components.
  • FIG. 1 a side view in section of a valve according to a first embodiment of the invention, as well as a symbolic diagram of a hydraulic system associated therewith, wherein the system is depicted in the active operating state in which the fluid is in a cold state;
  • FIG. 2 is a travel distance-temperature graph of a thermal element as part of the valve according to the invention.
  • FIG. 3 is a system pressure-temperature graph of a valve according to the invention.
  • FIG. 4 is a more simplified schematic side view in section, as compared to FIG. 1 , which shows the first exemplary embodiment in the inactive operating state;
  • FIG. 5 is a more simplified side view in section, as compared to FIG. 1 , which shows the first exemplary embodiment in the active operating state, in which the fluid that is to be cooled is warm;
  • FIG. 6 is a more simplified schematic side view in section, as compared to FIG. 1 , which shows the first exemplary embodiment in the operating state of the pressure cut-off in the event of an overload;
  • FIG. 7 is a side view in section of a valve according to a second exemplary embodiment of the valve according to the invention, as well as a symbolic diagram of the hydraulic system associated therewith, wherein the inactive operating state is shown;
  • FIG. 8 is a more simplified schematic side view in section, as compared to FIG. 7 , of the valve of the second exemplary embodiment, wherein the active operating state in which the fluid is cold is depicted;
  • FIG. 9 is a more simplified schematic side view in section, as compared to FIG. 7 of the valve of the second exemplary embodiment, wherein the active operating state in which the fluid that is to be cooled is warm is shown;
  • FIG. 10 is a more simplified schematic side view in section, as compared to FIG. 7 , of the valve of the second exemplary embodiment, wherein the operating state is depicted having a pressure cut-off in the event of an overload.
  • FIG. 1 shows, shows, in part, a sectional view, and in part, a symbolic depiction of a first exemplary embodiment of the valve solution according to the invention.
  • the valve 10 has a valve housing 12 made up of three parts 14 , 16 and 18 allowing a practical assembly of the valve housing 12 along corresponding vertically extending separation points 20 .
  • the connectivity solution is not shown in detail.
  • a supply or pump connection P, a working connection or utility connection A, as well as a tank connection T are located on the underside of the valve housing 12 , which tank connection has a tank or ambient pressure.
  • two fluid ports or connections 22 , 24 are present on the left side of the valve housing part 16 as viewed in the direction shown in FIG. 1 .
  • a fluid for example in the form of a hydraulic oil, can flow in the direction indicated by the arrow.
  • Two fluid chambers 26 , 28 which are disposed one behind the other, are present within the valve housing part 18 in the longitudinal direction thereof.
  • a control piston 30 which can be movably guided in a longitudinal direction, is present in the two fluid chambers 26 , 28 and within the inner surface of the valve housing 12 .
  • three piston components 34 , 36 and 38 are present on the piston rod 32 of that control piston, which piston components are spaced apart from one another in an axial direction, and are wider than the piston rod 32 in the radial direction.
  • the two annular or cylindrically-shaped piston components 34 , 36 have the same outer circumference.
  • the piston component 38 by contrast, has a diameter that is reduced accordingly, so that piston component 38 is able to move in the fluid chamber 28 .
  • the outer circumference of fluid chamber 28 is likewise reduced accordingly with respect to the fluid chamber 26 .
  • the fluid chamber 28 forms a spring chamber, in which an energy store in the form of a compression spring 40 is held.
  • the solution according to the invention may also omit the compression spring 40 .
  • the piston rod 32 projects axially over or beyond the piston component 38 , in this respect, the piston rod forms a stop surface 39 at the free front surface thereof for possible contact with the aligned inner surface of the valve housing 12 at this location.
  • the piston rod 32 transitions directly into the piston component 34 .
  • the piston component 34 rests against a limit stop 42 , which is designed in such a way that a further fluid chamber 44 is formed, having a smaller diameter than the adjacent fluid chamber 26 .
  • a sudden change in diameter in the valve housing part 16 forms a step with respect to the valve housing part 18 at the specified separation point 20 .
  • Separation point 20 extends vertically and serves as a limit stop 42 for the entire control piston 30 insofar as the control piston is located in the left stop position thereof as shown in FIG. 1 .
  • An additional piston component 46 adjoins the left piston component 34 of the control piston 30 .
  • Piston component 46 is reduced in diameter accordingly with respect to piston component 30 such that it can be movably guided in a longitudinal direction in the additional fluid chamber 44 .
  • the additional piston component 46 is an integral component of the piston component 30 and is reduced in diameter along a step 20 .
  • the piston rod 32 could also carry through, and for the two piston components 38 and 46 to be designed such that they are integral to one another. As viewed in the direction shown in FIG.
  • the additional piston component 46 has a stop element 48 on the left side thereof, which can stop element be brought into abutment with a stop surface on the front surface of a choke piston 50 as a function of the movement positions of the piston assembly within the valve housing.
  • the choke piston 50 can be movably guided in a longitudinal direction within the fluid chamber 44 and has two annular piston components 52 , 54 , which, as viewed in the axial direction, are held spaced apart from one another via a piston rod component 56 , which is disposed therebetween. That choke piston 50 is preferably integrally formed.
  • Stop 58 is created by a reduction in diameter of a fourth fluid chamber 60 , which, as viewed in the axial direction of the piston assembly, is delimited on the right side thereof by the front surface of the piston component 52 of the choke piston 50 , and which is delimited on the other, opposite side thereof by a thermal element 62 .
  • an actuating element 64 passes through the fourth fluid chamber 60 , as viewed in the axial direction of the valve 10 , which actuating element 64 is associated with a thermal element 62 .
  • the thermal element 62 is received in an element receptacle 66 within the valve housing part 16 .
  • the thermal element 62 is able to move, contrary to the action or against the biasing force of an additional energy store in the form of an additional compression spring 68 , to the left, as viewed in the direction shown in FIG. 1 , as a function of the operating state of the valve 10 .
  • the thermal element 62 is then spaced at the right, front end surface thereof at a distance from a stop surface 70 , which will be described in greater detail below.
  • the additional compression spring 68 is supported at one free end thereof on the thermal element 62 and at the other free end thereof on the interior of the valve housing part 14 , which closes off the valve housing 12 from the outside in the manner of an end cap.
  • the thermal element 62 is enclosed by or surrounded by an annular chamber 72 , into which the fluid ports 22 , 24 discharge.
  • An additional, third energy store in the form of a compression spring extends between the choke piston 50 and the additional piston component 46 , which third energy store is a working spring 74 .
  • the supply or pump connection P as well as the working connection A discharge is at least in part into the first fluid chamber 26 delimited at its edges or longitudinal ends by the two piston components 36 , 38 .
  • the tank connection T discharges into the first fluid chamber 26 in the region between the two piston components 34 and 36 of the control piston 30 .
  • connection line 76 discharges between that part of the first fluid chamber 26 extending between the two piston components 36 and 38 , extends through the valve housing 12 in the upper region thereof in a longitudinal direction, and discharges at its other end into the third fluid chamber 44 in that region of third fluid chamber 44 delimited by the two piston components 52 and 54 of the choke piston 50 .
  • the connection line 76 may, instead, be disposed in a rear region (not shown) of the valve housing 12 .
  • second connection line 78 is provided on the underside of the valve housing 12 , extends in an axial direction parallel to the connection line 76 , discharges at one free end thereof into the tank connection T, and discharges at the other free end thereof into the fourth fluid chamber 60 .
  • transverse branch lines 80 , 82 originate at the connection line 78 .
  • the branch line 80 discharges into the working spring chamber 84 in which the working spring 74 extends.
  • the branch line 82 extends and opens in the direction of the third fluid chamber 44 .
  • an adjustment cylinder 86 which is designed as a differential cylinder, is connected to the valve 10 , which will be explained in greater detail below.
  • the piston 88 of the adjustment cylinder 86 separates a piston chamber 90 from a rod chamber 92 in a conventional manner within the cylinder housing such that this separation is fluid-tight.
  • a return spring 96 is provided within the rod chamber 92 , through which a control rod 94 passes.
  • Control rod 94 is preferably actuated by the piston 88 , as an integral component thereof.
  • the return spring seeks to move the piston 88 in the direction of the unloaded state of the return spring, from right to left as viewed in FIG. 1 .
  • the control rod 94 which is designed as a piston rod, in conjunction with the adjustment or variable displacement cylinder, forms the adjusting device (pivot angle SW) of a variable displacement pump 98 , which may be designed as an axial piston machine, for example.
  • An electric motor 100 may serve as a drive for the variable displacement pump 98 , which may be a fixed speed motor, but may also be a variable speed motor. Instead of an electric motor, another drive source may also be used.
  • the pump is assumed to have a constant drive speed, although this drive speed is not necessarily a requirement in actual operation.
  • the variable displacement pump 98 removes the hydraulic fluid from the tank T and can supply this fluid at the end thereof, via a junction point 102 , in the direction of the pump connection P, and thus supplies fluid to a valve.
  • a screen or choke 106 is connected in feed line 104 as a pressure differential or input choke.
  • the rod chamber 92 of the adjustment cylinder 86 is connected such that it can conduct fluid, and a hydraulic motor 108 is connected on the opposite side of the junction point 102 , which motor serves as a fan drive and drives a fan blade 110 in the manner of a rotor.
  • the fluid, which is transported from the variable displacement pump 98 through the hydraulic motor 108 then flows out on the tank side T.
  • the volume of air flow which is generated by the fan blade 110 in a conventional manner, flows through a heat exchanging device 112 , which may be designed as a plate heat exchanger, for example, to which a hydraulic circuit 114 is connected.
  • Hydraulic circuit 114 serves to actuate a hydraulic work device, which is not depicted in greater detail here, for example.
  • the fan cools the fluid of the hydraulic circuit, which fluid is transported through the exchanging device 112 by an additional pump device, which is not depicted in greater detail here.
  • the hydraulic circuit 114 may be connected on the input side to the first fluid port 22 , and on the output side to the second fluid port 24 , of the valve 10 via fluid passages, which are not depicted in greater detail here.
  • the temperature in a separate fluid circuit can be reduced via the first and second fluid port 22 and 24 , which circuit only indirectly reflects the operating temperature situation in the hydraulic circuit 114 .
  • the piston chamber 90 of the adjustment cylinder 86 is connected to the working connection A via an additional connection line 116 .
  • the compression spring 40 in the second fluid chamber 28 may also be omitted.
  • a damping choke 118 is connected in fluid communication between the utility connection A and the tank connection T within the valve housing 12 .
  • the fluid chamber 28 should be discharged towards the tank side T, which is not depicted.
  • FIG. 4 shows the valve 10 and the associated hydraulic system in an inactive operating state.
  • the drive speed of the actuating pump 98 n An O .
  • the variable displacement pump 98 is adjusted to a full volume flow rate thereby, which is to say, the pivot angle SW of the variable displacement pump 98 is maximized.
  • the control piston 30 which is designed as a differential area piston, is thereby held in the right-hand A-T position by the working spring 74 , so that the working connection A, and thus the piston chamber 90 , of the actuating cylinder 86 are connected to the tank connection T. Due to the tank connection to the piston chamber 90 that is created, the piston 88 , which is guided in the actuating cylinder 90 , is held in the position thereof that corresponds to the maximum pivot angle SW by the return spring 96 .
  • the return spring 96 need not be present in the actuating cylinder 86 , since actuating systems can certainly be implemented without a spring return.
  • a permanent connection is between the working connection A and the tank connection T via the connection formed in the valve housing 12 via the damping choke 118 .
  • the choke piston 50 lies at a limit stop 58 (see FIG. 4 ) in the form of a reduction in diameter in the interior of the valve housing 12 .
  • the system pressure p 0 which builds up at the supply connection P is thus not lowered via the connection line 76 , and therefore, is exerted at a specifiable intensity on the differential pressure surfaces of the control piston 30 .
  • Control piston 30 is moved against the working spring 74 by the total hydraulic force that arises, and as a result, the P-A connection is opened, as shown in FIG. 1 .
  • the volume flow rate which results from the pressure gradient between the supply connection P and the working connection A, together with the adjustment piston 88 , formed on the differential piston, exerts a force on the large piston surface. If this force exceeds the action of force of the annular piston surface, which is subjected to pressure on the side of the piston rod, and which is thus the smaller annular piston surface, the adjustment piston 88 is displaced in the direction of the end position thereof that is on the right as depicted in FIG. 1 .
  • the volume of the adjustment cylinder 86 on the side of the piston rod is initially brought to a minimum, whereby the displacement volume of the variable displacement pump 98 is first reduced to a minimum, in that the piston 88 of the actuating cylinder 86 modifies the pivot angle SW towards smaller values.
  • the self-adjusting system pressure p 0 substantially corresponds to the sum of the forces from the relatively weak preloaded working spring as well as the necessary actuating forces of the pump adjustment mechanism and ideally falls below the minimum pressure required by the driving hydraulic motor 108 to start up the fan 110 .
  • the actuating element 64 of the thermal element 62 is at the minimum adjustment length thereof, which is to say, it is fully retracted.
  • F min is the force that results from the minimum adjustment length, which force is exerted on the choke piston 50 , and which can be assumed to be approximately zero, when the fluid is in a cold state, not otherwise specified.
  • this situation means that, in the case that the fluid is cold, the choke piston 50 does not change its position with respect to the position thereof in the inactive operating state according to FIG. 4 , so that the lines 76 and 78 are separated from one another by the closed control edge, as described above. A change in the state only occurs as a result of an increase in temperature.
  • the travel distance-temperature graph of the thermal element 62 shown in FIG. 2 is intended to clarify the function of the thermal element 62 , and shows a first range, having a regular travel distance S reg , which increases with a first slope, here, nearly 1, in a linear manner with the temperature T Fluid of the fluid, and an adjoining second range with an irregular travel distance S over , which increases with a second slope, which is reduced as compared to the first slope, in a linear manner with the temperature T Fluid of the fluid up to a maximum value.
  • the regular travel distance S reg thereby corresponds to a movement of the thermal element 62 or the actuating element 64 thereof in the control range, and accordingly, the irregular travel distance S over corresponds to an excess movement of the thermal element 62 or the actuating element 64 connected thereto.
  • a displacement of the choke piston 50 occurs in accordance with the extension of the travel distance of the actuating element 64 of the thermal element 62 , so that an increased initial load is exerted on the control piston 30 via the working spring 74 .
  • the increased force of the working spring 74 moves the control piston 30 in FIG. 5 to the right, as a result of which the control edge on the piston component 36 increasingly reduces the P-A fluid connection from the supply connection P to the working connection A and further, to the piston chamber 90 of the actuating cylinder 86 .
  • movement of the piston 88 of the actuating cylinder 86 increasingly increases the pivot angle SW of the variable displacement pump 98 to increase the displacement volume accordingly.
  • the choke piston 50 increasingly opens the connection between the connection line 76 and the second connection line 78 , which extends to the tank connection T, using the control edge located on the piston component 54 .
  • the control pressure that is exerted upon the control piston 30 behind the input choke 106 in the fluid chamber 26 is lowered, which means that the system pressure p 0 that exists on the pressure side of the variable displacement pump 98 must increase disproportionately to maintain the balance of forces at the control piston 30 .
  • FIG. 3 what is actually a linear pressure-temperature characteristic curve is thereby made non-linear, and instead, is adapted to the increasing characteristic curve of the fan, which increases cubically (see FIG. 3 ).
  • the working point of the inactive system is indicated as I
  • the working point of the active system in the case that the fluid is cold is indicated as II
  • a working point within the control range in the case that the fluid is warm is indicated as III.
  • an additional pressure P 2 is needed to maintain the control pressure prevailing in the control range due to the reduction in pressure via the choke piston 5 .
  • the system pressure P 0 there is a corresponding increase in the system pressure P 0 with a corresponding increase in the fan speed generated by the hydraulic motor 108 .
  • FIG. 6 shows an operating state, in which the system pressure P 0 has increased to a value, which corresponds to an overload state.
  • the pressure which prevails here in the fluid chamber 26 and is exerted on the control piston 30 , generates a piston force that is directed towards the left, as depicted in FIG. 6 , of an intensity, at which the stop element 48 (see FIG. 1 ) of the piston is brought into full contact with the choke piston 50 .
  • stop element 48 rests against the choke piston 50 so that the pressure is exerted on the actuating element 64 via the choke piston 5 and is therefore exerted on the thermal element 62 .
  • FIGS. 7 through 9 show a second exemplary embodiment.
  • This second exemplary embodiment differs from the first in that an internal fluid feed is provided in the valve housing 12 via a fluid line 27 from the supply connection P to the port 22 on the thermal element 62 , and from port 22 , via a return line 29 , to the second connection line 78 , and therefore to the tank connection T. Since, in this way, an internal flushing fluid line is provided for the fluid, which defines the temperature of the thermal element, the thermal element can be omitted on the external port 22 , as is shown in the drawing.
  • the internal fluid connection represents an alternative to the external port in the event that the fan drive is desired to be operated in a completely self-sufficient manner.
  • the internal fluid line 27 is connected to the supply connection P via an input choke 31 .
  • a second input choke 33 is located between the supply connection P and the fluid chamber, which second input choke is adjacent to the piston component 38 .
  • a further difference as compared to the first example is that a separation of the control fluid and actuating fluid is formed behind the supply connection P in that the control piston 30 has an intermediary piston component 35 between the piston component 38 at the end and the piston component 36 . This intermediary piston component has the same effective piston surface as the piston component 36 .
  • a fluid branch 37 which branches off from the supply connection P, discharges into the fluid chamber 26 between the piston component 36 and the intermediary piston component 35 .
  • control pressure which is operative in the fluid chamber 26 as a control force on the control piston 30
  • actuating pressure which is exerted at the working connection A via the fluid branch 37 that branches off, in a manner that is controlled by the piston component 36
  • a correspondingly lower control pressure having lower required spring rates at the control piston 30 allows for a low control oil consumption, and to this extent, a reduced loss in the level of efficiency at the control valve.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Temperature-Responsive Valves (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Fluid Mechanics (AREA)
  • Sliding Valves (AREA)
  • Multiple-Way Valves (AREA)
US14/648,929 2013-01-04 2013-12-21 Valve for the temperature-dependent control of at least one hydraulic load Expired - Fee Related US9920778B2 (en)

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DE102013000121.8 2013-01-04
DE102013000121 2013-01-04
DE102013000121.8A DE102013000121A1 (de) 2013-01-04 2013-01-04 Ventil zur temperaturabhängigen Ansteuerung mindestens eines hydraulischen Verbrauchers
PCT/EP2013/003936 WO2014106535A1 (de) 2013-01-04 2013-12-21 Ventil zur temperaturabhängigen ansteuerung mindestens eines hydraulischen verbrauchers

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Publication number Priority date Publication date Assignee Title
US20190112787A1 (en) * 2017-10-16 2019-04-18 Deere & Company Temperature responsive hydraulic derate

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EP3069798B1 (de) * 2015-03-17 2019-08-14 Wacker Neuson Produktion GmbH & Co. KG Steuervorrichtung für schwingungserreger für bodenverdichtungsvorrichtungen
DE102015010849A1 (de) * 2015-08-20 2017-02-23 Hydac Fluidtechnik Gmbh Ventilvorrichtung zum Steuern eines Fluidstroms sowie Stromregelventil
KR102399571B1 (ko) * 2015-09-09 2022-05-19 삼성디스플레이 주식회사 표시 장치 및 그 구동 방법
US10678276B2 (en) 2016-11-16 2020-06-09 Hydac Fluidtechnik Gmbh Valve device for controlling a fluid flow and flow control valve

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US3359831A (en) * 1965-05-20 1967-12-26 Gen Motors Corp Multiple speed fan drive
US3913831A (en) * 1974-03-22 1975-10-21 Deere & Co Oil cooler bypass valve
US4062329A (en) * 1976-07-29 1977-12-13 The United States Of America As Represented By The Secretary Of The Army Fan drive system
US4488680A (en) * 1982-03-31 1984-12-18 Aisin Seiki Kabushiki Kaisha Thermally responsive valve device
DE3407747A1 (de) 1984-03-02 1985-09-12 Robert Bosch Gmbh, 7000 Stuttgart Druckregler fuer eine verstellbare pumpe
US4699571A (en) * 1984-11-28 1987-10-13 Mannesmann Rexroth Gmbh Control valve for a variable displacement pump
DE19601376A1 (de) 1996-01-16 1997-07-17 Rexroth Mannesmann Gmbh Meßfühlerschaltung
US5876185A (en) * 1996-11-20 1999-03-02 Caterpillar Inc. Load sensing pump control for a variable displacement pump
US5800130A (en) * 1996-12-19 1998-09-01 Caterpillar Inc. Pressure control system for a variable displacement hydraulic pump
US6820817B2 (en) * 2002-02-09 2004-11-23 Hyundai Motor Company Adjustable electronic thermostat valve
DE102010007247A1 (de) 2010-02-09 2011-08-11 Hydac Filtertechnik GmbH, 66280 Hydraulischer Lüfterantrieb
US9441744B2 (en) * 2010-12-23 2016-09-13 Dana Canada Corporation Valve apparatus

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20190112787A1 (en) * 2017-10-16 2019-04-18 Deere & Company Temperature responsive hydraulic derate
US10633827B2 (en) * 2017-10-16 2020-04-28 Deere & Company Temperature responsive hydraulic derate

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AU2013372034A1 (en) 2015-05-28
WO2014106535A1 (de) 2014-07-10
CN104884811B (zh) 2017-12-19
JP2016502058A (ja) 2016-01-21
CN104884811A (zh) 2015-09-02
DE102013000121A1 (de) 2014-07-10
EP2941571A1 (de) 2015-11-11
AU2013372034B2 (en) 2017-04-20
CA2893301A1 (en) 2014-07-10
JP6321679B2 (ja) 2018-05-09
US20150308468A1 (en) 2015-10-29
HK1210250A1 (zh) 2016-04-15

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